SF 

767 


AI^aaiTIGAL  CATTL:^   DIP3 


U.S.D.A.    iSul,    603 


By  :^.    M.    Ghapin 


August   1914 


..,i.,i,ili;;:        -5^75  7 .^^.o.-^-^""^-  Mai«  uteM, 


LIBRARY 
G 


U.S.DEPARTMENT  OF  AGRICULTURE 


603 


Contribution  from  the  Bureau  of  Animal  Industry,  A.  D.  Melviri,  Chief. 
August  14.  1914. 

ARSENICAL   CATTLE    DIPS: 

METHODS  OF  PREPARATION  AND  DIRECTIONS  FOR   USE. 
By   Robert  M.  Chapin, 
,,  Senior  Biochcntist,  Biochemic  Division. 

INTRODUCTORY. 

This  bulletin  is  intended  to  be  a  handbook  for  the  user  of  arsenical 
cattle  dips.     It  aims  to  include  in  brief  but  ample  form  general  in- 
formation, formulas,  tables,  and  practical  hints  bearing  on  the  prepa- 
ration and  management  of 
[arsenical  dipping  solutions, 
kit    to    this    field    it     is 
strictly  limited.  Those  who 
Hesire  a  popular  account  of 
[the    life    history     of    the 
[Texas- fever  tick  and  of  its 
Irelation   to   cattle    are   re- 
ferred to  a  previous  bulle- 
|in  (Farmers' Bulletin  498) 
|issued  by  the  department, 
'he  same,  as  well  as  an- 
)ther  previous  publication 
[(Bureau  of  Animal -Industry  Circular  207),  contains  plans  and  speci- 
Ications  for  the  construction  of  dipping  vats,  together  with  directions 
for  the  management  of  cattle  in  connection  with  dipping. 

PROPERTIES  OF  SUBSTANCES  USED  IN  MAKING  DIPS. 
Making  a  dip  is  simply  a  manufacturing  j^roposition.     Xo  manu- 
facturer can  expect  to  get  the  best  results  unless  he  is  somewhat 
icquainted  with  important  facts  regarding  his  raw  materials. 

White  arse?iic,  also  known  as  arsenic  trioxid,  arsenious  or  arsen- 
)us  oxid  or  anhydrid,  should  always  be  purchased  in  the  form  of 
fine  powder,  and  under  a  g-uaranty  of  99  per  cent  purity.  Water, 
iven  when  boiling,  will  dissolve  only  a  little  of  it,  and  that  slowly, 
)ut  by  the  use  of  certain  other  chemicals  white  arsenic  may  be  readily 
md  abundantly  brought  into  solution. 

White  arsenic  is  a  violent  poison,  and  users  of  it  must  never  allow 
familiarity  to  beget  carelessness.  It  may  be  absorbed  into  the 
system  and  cause  injury  or  death,  either  through  the  mouth,  the 

47702°— 14 

487^60 


(S^^ 

\^^ 

Fig.  1. — Map  of  the  United  States,  the  shaded  area 
showing  the  territory  to  which  this  bulletin 
applies. 


2  farmers'  bulletin  608. 

lujigs,  or  the/.ski.n;  tl'ontfwj't 'neither  the  dry  powder  nor  the  solution 
should  be  allV)\vVd  t?)*rei^i':ii*n*oii.thc  skin.  The  breathing  in  of  dust 
arising  froijrrrltiP,*;Tp\-.;6o\Ttl'i»r.  (firing  handling  must  be  avoided, 
while,  if'caftle  Vre  iJeiiig  s'prayed,  neither  the  operator  nor  the  cattle 
should  inhale  any  of  the  spray.  Moreover,  from  a  boiling  solution 
arsenic  may  be  thrown  out  as  a  fine  spray  and  also,  under  certain 
conditions,  as  the  very  poisonous  gas  "  arsin.''  Hence,  concentrated 
dips  should  be  prepared  only  in  thoroughly  ventilated  places,  while 
all  work  should  be  done  on  the  windward  side  of  the  kettle  and  as 
far  from  it  as  practicable. 

If  arsenic  in  any  form  has  been  swallowed,  medical  attention  is 
to  be  obtained  as  soon  as  possible;  but  since  promptness  of  action  is 
of  very  great  importance  and  medical  attention  is  not  always  readily 
available,  it  is  best  for  all  who  use  arsenical  dips  to  be  familiar  ^ith 
first-aid  treatment.  The  United  States  Dispensatory  (nineteenth 
edition)  has  the  following  to  say  in  this  matter: 

If  the  antidote  *  *  *  be  not  directly  at  band,  free  voinitinp  sbould  be 
induced  by  tbe  finger,  tbe  featber  part  of  a  quill,  and  the  aduiinistratiou  of  an 
emetic;  *  ♦  *  Demulcent  drinks  sbould  be  freely  given,  .such  as  milk,  wbite 
of  eggs  and  water,  or  flour  and  water,  which  serve  to  encourage  the  vomiting 
and  to  envelop  the  poison. 

The  antidote  having  been  faithfully  applied,  tbe  subsequent  treatment  con- 
sists in  the  administration  of  mucilaginous  drinks  and  the  treatment  of 
symptoms  as  they  arise. 

*  ****** 

The  antidote  above  referred  to  is  *  *  *  ferric  hydrodUl  with  mnuncsium 
oxid  in  the  moist  or  pulpy  state.  As  soon  as  it  is  ready  it  must  be  given  in 
doses  of  a  tablesi>oonful  to  an  adult,  of  a  dessertspoonful  to  a  child,  every 
five  or  ten  minutes  until  the  urgent  symptoms  are  relieved.  *  *  *  Its 
efficacy  is,  of  course,  greater  the  sooner  it  is  administered  after  the  ingestion 
of  the  poison;  but  even  after  delay  its  use  will  prove  advantageous  so  long 
as  any  portion  of  the  p(nson  still  remains  in  the  stomach.  ♦  ♦  ♦  It  should 
be  an  invariable  rule  to  prepare  the  antidote  at  the  time  It  is  waiittnl  from 
materials  always  kejit  at  hand.  •  ♦  ♦  'phe  best  antidote  known  is  the 
combination  of  ferric  hydroxid  with  magne.sium  oxid  now  recognized  by  the 
U.  S.  Pharmacopoiia. 

The  materials  for  the  antidote  referred  to  can  be  supplied  by  any 
prescribing  jjharmacist,  contained  in  two  l)ottles.  In  this  separated 
form  the  antidote  keeps  well,  and  when  an  emergency  calls  for  its 
u.so  all  that  is  necessiuy  is  to  mix  thoroughly  (he  contents  of  the 
two  bottles  and  to  administer  as  directed.  But  in  any  case  medica^ 
attention  must  be  obtained  as  soon  as  possible. 

Sodium  carhonate. — Also  known  as  sal  soda  or  washing  soda, 
when  fresh  consists  of  colorless  trans|>»irent  crystals.  On  keeping, 
unless  lightly  closed  from  the  air,  it  tends  to  lose  its  crystalline 
apix-aranc*".  and  to  fall  to  a  white  powder.  This  change  is  due 
morcly  to  the  fact  that  the  crystals  carry  a  large  amount  of  com- 
bined water  (water  of  crystallization),  and  on  exposure  to  the  air 


ARSENICAL    CATTLE    DIPS.  'S 

much  of  this  water  may  evaporate  with  consequent  destruction  of 
the  crystalline  form.  The  soda  itself  is  in  no  way  affected  by  this 
loss  of  water,  except  that  it  really  becomes  stronger,  weight  for 
weight. 

Another  form  of  sodium  carbonate,  called  "  monohydrated  sodium 
carbonate,"  also  occurs  in  commerce  in  the  form  of  a  white  crystalline 
granular  powder.  It  contains  only  a  small  amount  of  water  of 
crystallization  and  is  practically  unaffected  bj^  exposure  to  air.  This 
form  of  soda  from  a  manufacturing  point  of  view  is  far  preferable 
to  sal  soda,  as  it  is  of  constant  and  permanent  composition,  and 
being  much  stronger,  weight  for  weight,  it  is  less  expensive  to  handle. 
When  using  monohydrated  soda  it  is  necessary  to  remember  that 
only  4rJ  pounds  are  needed  to  do  the  same  work  as  10  pounds  of 
sal  soda. 

Pine  tar. — Pine  tar  when  fresh  is  semiliquid,  but  with  age  becomes 
granular  and  nearly  solid,  in  which  condition  it  is  of  less  value. 
Mixed  with  it  is  always  more  or  less  water  of  decidedly  acid  prop- 
erties (pyroligneous  acid),  which  on  standing  tends  to  float  on  the 
surface  and  should  be  dipped  or  poured  off  before  the  tar  is  used. 

Tar  is  heavier  than  water  and  when  stirred  with  it  usually  forms 
a  very  poor  mixture  from  which  most  of  the  tar  rapidly  settles  out, 
but  when  the  water  is  of  just  the  right  temperature  and  somewhat 
alkaline  a  fairly  stable  suspension  may  generally  be  obtained.  Wlien 
previously  treated  with  an  amount  of  caustic  alkali  sufficient  to  com- 
bine with  a  considerable  proportion  of  the  tar  acids,  or  when  blended 
with  soap,  the  tar  easily  mixes  with  water  and  then  forms  a  good  and 
permanent  emulsion. 

Caustic  soda. — Also  known  as  sodium  hydroxid,  or  sodium  hydrate, 
on  account  of  its  wide  range  of  application  by  chemists,  pharmacists, 
and  manufacturing  industries  occurs  commercially  in  a  number  of 
different  forms,  as  powder,  flakes,  solid  masses,  or  broken  fragments ; 
m  color  ranging  from  pure  white  to  grayish  or  brownish  tints.  For 
the  use  of  chemists  and  pharmacists  it  is  put  up  in  glass  bottles;  for 
industrial  purposes  it  is  supplied  in  various  sized  cans  or  drums  of 
thin  sheet  iron.  The  latter  is  the  variety  that  should  be  purchased 
for  making  dip.  Its  large  output  and  wide  use  render  it  easily 
obtainable  almost  everywhere — far  more  so  than  white  arsenic.  The 
10-pound  can  is  the  best  size  to  buy  for  home  use  in  preparing  dips ; 
larger  consumers  can  probably  handle  the  material  in  larger  drums 
conveniently  and  of  course  more  economically.  The  purchaser  must 
make  sure  that  the  contents  of  the  drum  he  contemplates  buying  are 
in  fragmentary  form,  or  granulated,  for  much  caustic  soda  is  run 
into  drums  in  a  melted  condition  and  on  cooling  forms  a  single  solid 
cake,  which,  though  satisfactory  for  factory  use,  is  not  adapted  for 
the  present  purpose.  It  should  always  be  purchased  under  a  guaranty 
of  not  less  than  85  per  cent  actual  caustic  soda. 


4  farmers'  BFLLETTX  603. 

Caustic  soda  is  an  intensely  active  and  pr>\vt'rful  substance.  When 
exposed  to  the  air  it  strongly  attracts  moisture,  increasing  in  weight 
and  becoming  pasty,  while  at  the  same  time  it  becomes  contaminated 
with  sodium  carbonate  through  ab.sorption  of  carbon  dioxid.  Hence 
it  must  always  be  purcliased  in  original  containers,  never  in  bulk; 
the  container  mu.st  not  be  opened  until  just  before  the  material  is 
to  be  used;  the  substance  must  not  be  allowed  to  stand  exposed  to 
the  air,  and  if  any  is  left  over  which  is  to  be  kept  for  subsequent 
use  it  must  be  immediately  transferred  to  a  tin  pail  provided  with  a 
tightly  fitting  cover,  such  as  a  lard  pail,  or,  best  of  all.  a  paint  pail 
with  a  friction  top. 

Owing  to  the  intense  chemical  activity  of  caustic  soda  it  is  ex- 
tremely corrosive  in  its  effect  upon  .skin  or  clothes,  and  upon  the  lungs 
if  dust  from  it  is  inhaled.  Therefore  it  is  necessaiy  to  handle  it 
gently  to  avoid  the  raising  of  dust  and  to  wash  off  at  once  with  wat^r 
any  which  may  touch  the  skin  or  clothing. 

Caustic  potash. — Also  known  as  potassium  hydroxid  or  hydrate,  is 
very  similar  in  its  properties  to  caustic  soda.  It  is  not,  however,  so 
widely  used  industrially,  and  is  decidedly  more  expensive  without 
being  any  better  for  the  present  purpose.  Therefore  it  should  be 
purchased  only  when  caustic  soda  happens  not  to  be  available.  In 
its  use  one  must  remember  that,  weight  for  weight,  it  is  less  efficient 
than  caustic  soda,  so  that  for  every  pound  of  the  latter  there  must  be 
employed  1.4  pounds  of  caustic  potash.  Like  caustic  soila.  it  must  be 
guaranteed  at  least  85  per  cent  pure. 

Lye. — This  is  a  term  employed  to  designate  a  grade  of  caustic  soda 
put  up  primarily  for  domestic  use,  such  as  making  soap  from  waste 
grease  and  for  general  cleansing.  Since  ordinarj'  buyers  of  this 
grade  of  goods  are  not  apt  to  be  able  to  judge  closely  of  its  quality, 
it  is  sometimes  of  very  inferior  grade,  though  not  necessarily  so. 
If  any  guaranty  regarding  its  purity  can  be  obtained,  it  may  be  used 
for  dip  making,  in  case  of  necessity,  in  the  same  proportions  as 
caustic  soda. 

THE  GENERAL  COMPOSITION  OF  DIPS. 

All  arsenical  cattle  dips  contain  arsenious  oxid  as  the  active  tick- 
killing  agent.  But  since  straight  ai"senious  oxid,  that  is,  M'hite  ar- 
senic, is  so  slightly  and  slowly  soluble  in  water,  it  is  necessary  to  use 
some  other  chemical  agent,  such  as  sodium  carbonate  or  hydroxid,  to 
bring  the  arsenious  oxid  into  solution.  In  this  way  the  white  arsenic 
is  changed  to  sodium  arsenite  if  either  sodium  hydroxid  or  sodium 
carbonate  is  employed,  oi-  to  potassium  ai'senite  if  the  corresponding 
potassium  compounds  are  used.  Starting  with  a  given  weight  of 
white  arsenic,  whether  it  is  converted  to  sodium  arsenite  or  to  potas- 
sium arsenite  appears  to  make  no  difference  in  the  action  of  the 
finished  dip. 


ARSENICAL   CATTLE   DIPS.  5 

After  the  white  arsenic  has  been  brought  into  sohition,  a  variety 
of  substances,  such  as  tar,  soap,  oils,  etc.,  may  be  added  with  one  or 
more  of  the  following  objects  in  view:  (1)  To  increase  the  effective- 
ness of  the  bath  against  ticks,  either  through  greater  penetrating 
power  or  better  adhesion,  or  through  repellent  action ;  (2)  to  render 
milder  the  effect  of  the  bath  upon  cattle;  (3)  to  denature  the  bath  so 
that  cattle  will  not  drink  it.  Proprietary  concentrated  dips  differ 
from  each  other  and  from  home-made  dips  essentially  only  in  the 
nature  and  amount  of  such  added  substances. 

MAKING  THE  BOILED  DIP. 

The  boiled  dip  has  been  recommended  for  use  in  two  strengths,  the 
baths  corresponding  to  which  will  be  termed  here  "  low-strength 
bath  "  and  "  high-strength  bath.'''  The  low-strength  bath  is  com- 
monly used  for  ordinary  tick-eradication  work  on  the  range,  the  cattle 
being  dipped  regidarly  every  two  weeks  for  possibly  several  months. 
The  high-strength  bath  is  used  to  treat  cattle  which  are  undergoing 
transportation  to  a  tick-free  region,  the  treatment  being  usually 
limited  to  only  two  dippings,  5  to  10  days  apart. 

To  make  500  ^  gallons  low-strength  bath  provide : 

Sal  soda* 24  pounds. 

White  arsenic,  99  per  cent  pure,  in  fine  powder 8  pounds. 

Pine  tar 1  gallon. 

Put  25  gallons  of  water  in  a  kettle  or  tank  of  40  to  50  gallons 
capacity,  heat  to  boiling,  and  add  the  sal  soda.  When  this  has  dis- 
solved add  the  white  arsenic,  then  boil  and  stir  for  15  minutes  or 
longer,  until  the  white  arsenic  has  entirely  disappeared.  If  intended 
for  immediate  use  cool  to  140°  F.  (by  the  addition  of  cold  water  if 
desired),  then  pour  in  the  pine  tar  in  a  thin  stream  while  constantly 
and  vigorously  stirring  the  solution.  Immediately  empty  the  liquid 
into  the  dipping  vat,  which  has  already  been  three-fourths  filled 
with  water,  and  stir  thoroughly. 

For  a  stock  solution  to  be  kept  on  hand  and  used  when  needed,  add 
no  tar,  but,  after  the  solution  of  arsenic  and  soda  has  become  entirely 
cold,  make  it  up  to  25  gallons  (see  method  on  page  7),  stir  well, 
let  settle,  and  draw  off  into  containers  which  can  be  well  closed. 
This  constitutes  "  low-strength  boiled  arsenic  stock,"  and  its  use  in  a 
diluted  dipping  bath  calls  for  a  "tar  stock,"  the  preparation  of 
which  is  described  on  page  7. 

High-strength  bath  or  high-strength  boiled  arsenic  stock  is  pre- 
pared in  exactly  the  same  way,  except  that  for  500  gallons  of  diluted 
bath  there  is  used  10  pounds  of  white  arsenic  and  25  pounds  of  sal 
soda  (or  11  pounds  monohydrated  sodium  carbonate). 

^  The  number  of  pounds  of  white  arsenic  needed  to  make  any  number  of  gallons  of  bath 
of  any  strength  may  be  obtained  from  Table  1,  on  page  11. 
*0r  monohydrated  sodium  carbonate,  lOJ  pounds. 


6  farmers'  bulletin  603. 

A  by-prcKluct  of  the  action  of  sodium  c:«rl»oiuile  vn  white  arsenic  is  the  gas 
carbon  dioxid.  The  esonjie  of  this  gas  is  attende<l  by  considerable  foaming 
of  the  solution,  so  the  kettle  must  be  generously  large,  and  the  operation  of 
boiling  must  have  constant  watching  to  prevent  the  liquid  from  frothing  over 
the  edge  of  the  kettle. 

The  kettle  or  tank,  utensils,  and  materials  must  be  perfectly  free  from  all 
greasy  or  oily  substances,  since  a  small  quantity  of  such  matter  is  sufficient  to 
form  a  coating  over  the  arsenic  and  thus  to  prevent  or  delay  its  solution. 

The  boiled  dip  may  be  made  perfectly  well  with  very  hard  water,  but.  in 
that  case,  some  residue  of  a  line  white  or  gray  powder  will  be  left  undissolved 
after  boiling.  This  residue  carries  no  arsenic,  but  arises  from  the  action  of  the 
sodium  carbonate  upon  compounds,  chiefly  of  lime,  in  the  water.  Examination 
of  the  liquid  after  boiling  for  a  few  minutes  with  the  .smla  before  the  arsenic 
has  been  addp<l  will  show  how  much  residue  may  be  e.xpected  from  this  source. 

MAKING  THE  S-B  DIP.' 

The  S-B  arsenical  dip  was  developed  by  the  present  writer  about 
two  years  ago  to  meet  certain  drawbacks  to  tlie  boiled  dip,  namely, 
(1)  the  necessity  for  boiling  large  amounts  of  liquid,  and  (2)  the 
impossibility  of  preparing  highly  concentrated  stock  solutions. 
Bureau  employees  in  the  field  have  given  the  preparation  a  thorough 
test  in  practical  dipping.  The  difference  between  the  S-B  dip  and 
the  boiled  dip  is  merely  in  the  formulas  and  methods  of  preparation, 
the  composition  of  the  diluted  baths  used  for  dipping  being  prac- 
tically the  same  in  both  cases. 

The  S-B  dip  is  prepared  in  two  parts  which  must  not  be  mixed 
except  in  the  diluted  dipping  bath,  (1)  arsenic  stock,  (2)  tar  stock. 

S-B  arsenic  stock  requires  the  following  materials  ready  to  hand 
before  starting: 

Pounds. 

Caustic  soda,^  at  least  85  per  cent  pure,  dry,  granulated 4 

White  arsenic,  99  per  cent  pure,  in  fine  powder 10 

Sal  soda,*  crystals 1 10 

In  a  5-gallon  kettle  or  metal  *  pail  place  the  4  pounds  of  caustic 
soda,  add  1  gallon  of  cold  water,  and  stir  with  a  stick  until  the  caustic 
soda  is  practically  all  dissolved.  Without  delay  begin  adding  the 
white  arsenic,  in  portions  of  a  pound  or  two  at  a  time,  as  fast  as  it 
can  be  dissolved  without  causing  the  solution  to  boil,  stirring  all  the 
time.  If  the  liquid  begins  to  boil,  stop  stirring  and  let  it  cool  slightly 
before  adding  more  arsenic.  The  secret  of  success  is  to  work  in  the 
arsenic  fast  enough  to  keep  the  solution  verv-^  hot — nearly  but  not 

^Abbreviated  from  "  self-boiled,"  the  name  betug  suKuestcd  by  tlie  fact  that  the  hcnt 
necessary  to  prcpnie  the  dip  Is  wholly  derived  from  chemical  action  bctwpcMi  the  raw 
materials.  ' 

"  Or  r»4  poiiuds  dry  caustic  potash  of  cipial  purity. 

"Or  4 J  poundH  monohydratcd  Bodluin  carlionate. 

<  Tlic  chcnilcnls  cmplo.Vfd  linvc  no  i-ITccI  upon  Iron.  Thoy  will,  however,  actively  (or 
rode  zinc,  tin,  or  Holdi-r ;  licncc  a  soltlcrcil  pall  raiiHt  bt-  watched  for  h-aks  and  Is  f:n- 
inferior  to  a  HeiinilesH  pall,  siiuuricd  from  a  sluulr'  shrel  of  Iron.  A  tinned  pall  Is  pre- 
ferred to  a  j;alvaiil/('(l  one,  but  a  plain  Iron  HeanilcHs  pull  or  an  Iron  kettle  should  be 
obtained   If  poHMlbli-. 


AESENICAL    CATTLE    DIPS.  7 

quite  at  the  boiling  point.  The  result  should  be  a  clear  solution, 
except  for  dirt.  If  the  liquid  persistently  remains  muddy  or  milky, 
it  may  be  because  the  operation  has  been  conducted  so  fast  that  much 
water  has  been  boiled  out  and  sodium  arsenite  is  beginning  to  ciys- 
tallize,  so  add  another  gallon  of  water  and  stir.  If  the  solution  does 
not  then  clear  up,  the  caustic  soda  must  have  been  very  low  grade, 
and  the  undissolved  substance  must  be  arsenic.  In  that  case,  put  the 
kettle  over  the  fire,  heat  nearly,  but  not  quite,  to  boiling,  and  stir. 
As  soon  as  the  solution  of  arsenic  is  complete,  dilute  to  about  4  gal- 
lons, add  the  sodium  carbonate,  and  stir  until  dissohed. 

Cautions  :  It  is  necessary  to  avoid  splashing.  Hence  never  work  hurriedly ; 
stir  deliberately  and  regularly;  do  not  dump  in  the  arsenic  and  sal  soda,  but 
carefully  slide  them  in  from  a  grocer's  scoop  held  close  to  the  side  of  the  pail 
and  to  the  surface  of  the  liquid.  Perform  the  whole  operation  in  a  well-ven- 
tilated place  and  avoid  inhaling  steam. 

After  the  solution  has  become  cold  add  water  to  make  it  to  exactly 
5  gallons,^  mix  well,  let  settle,  and  draw  off  into  containers  which 
can  be  tightly  corked  or  otherwise  closed.  Jugs  or  demijohns  are 
best,  but  tin  cans  will  serve  if  occasionally  inspected  for  leaks  which 
may  occur  after  a  time  through  the  action  of  the  solution  upon  the 
solder  of  the  can. 

Tar  stock  appropriate  for  use  with  either  S-B  arsenic  stock  or 
boiled  arsenic  stock  is  prepared  thus: 

In  a  capacious  metal  pail  dissolve  three- fourths  of  a  pound  of  dry 
caustic  soda  or  concentrated  lye  (or  1  pound  of  dry  caustic  potash) 
in  1  quart  of  water,  add  1  gallon  of  pine  tar,  and  stir  thoroughly 
with  a  wooden  ]3addle  until  the  mixture^  which  at  first  looks  streaked 
and  muddy,  brightens  to  a  uniform  thick  fluid  somewhat  resembling 
molasses.  Test  it  by  letting  about  a  teaspoonful  drip  from  the  pad- 
dle, into  a  glass  of  water  (a  glass  fruit  jar  or  a  wide-mouth  bottle  will 
serve)  and  stimng  thoroughly  with  a  sliver  of  wood.  It  should  mix 
perfectly  with  the  water.  Globules  of  tar  which  can  be  seen  by 
looking  at  the  glass  from  underneath  and  which  can  not  be  blended 
with  the  water  by  repeated  stirring  indicate  that  more  caustic-soda 
solution  is  needed.  In  that  case  make  up  more  caustic-soda  solution 
of  the  same  strength  and  add  it,  not  more  than  a  pint  at  a  time,  and 
with  thorough  stirring,  until  the  desired  effect  is  produced. 

If  an  appropriate  glass  vessel  for  making  tlie  test  is  not  at  hand,  a 
little  of  the  mixture  may  be  taken  between  the  fingers,  then  dip  the 
fingers  under  water  and  try  to  rub  off  the  tar.  It  should  leave  the 
fingers  perfectly  clean  after  a  little  rubbing  with  water.  If  an  oily 
coating  remains,  more  caustic-soda  solution  is  needed.  Such  an  extra 
addition  of  caustic  soda  will  be  required  only  in  case  of  a  very  low- 

1  Best  done  by  previously  determining  by  measurement  the  depth  of  5  gallons  of  water 
in  the  kettle.  Set  the  kettle  exactly  level  and  mark  the  depth  on  a  stick  held  vertically 
on  the  center  of  the  bottom. 


I 


8  farmers'  BULLETTN  608. 

^aatle  chemical  or  a  very  hi<jrhly  acid  tar.     The  tar  stock  should  be 
kept  in  closed  containers,  .such  as  a  pail  with  a  friction  top. 

DILUTING   THE  DIP  TO  FORM  A   BATH. 

Whatever  the  dip  used,  whether  lx)iled  dip,  S-B  dip.  or  a  pro- 
prietary preparation,^  certain  facts  must  be  borne  in  mind  and  a  cer- 
tain routine  followed  in  preparing  baths  for  dipping.  .Ul  concen- 
trated arsenical  preparations  are  considerably  heavier  than  water, 
and  unless  properly  introduced  into  the  dipping  vat  tend  to  make 
their  way  to  the  bottom,  after  which  it  is  difficult  to  get  an  even  mix- 
ture. In  preparing  a  diluted  bath  it  is  necessary  first  to  fill  the  vat 
with  water,  leaving  just  enough  space  below  the  full  water  line  for 
the  necessary  volume  of  concentrated  dip.  Then  the  desired  amount 
of  concentrated  dip  is  to  be  poured  in  a  thin  stream  evenly  all  over 
the  surface  of  the  water — except,  of  course,  at  the  shallow  exit  end 
of  the  vat — after  which  a  few  minutes  of  brisk  stirring  will  make 
certain  that  the  bath  is  of  uniform  strength  throughout.  If  tar 
stock  is  used,  as  in  the  case  of  the  S-B  dip,  the  tar  stock  is  to  be  added 
before  the  arsenic  stock  and  may  be  put  in  when  the  vat  is  about 
three-fourths  filled  with  water.  Tar  stock  should  always  be  mixed 
with  two  or  three  times  its  volume  of  water  before  being  added  to 
the  vat. 

The  dilutions  at  which  the  various  concentrated  stocks  will  be  used 
are  as  follows: 

Boiled  arsenic  stock,  containing  either  8  pounds  (low  strength)  or 
10  pounds  (high  strength)  white  arsenic  in  25  gallons,  for  the  cor- 
responding strength  bath,  1  gallon  added  to  every  19  gallons  wat^r 
(2^  pints  to  5  gallons). 

S-B  arsenic  stock,  containing  10  pounds  white  arsenic  in  5  gallons, 
for  low-strength  bath  1  gallon  added  to  ever}'  124  gallons  wafer 
(5^  fluid  ounces  to  5  gallons)  ;  for  high-strength  bath  add  1  gallon 
to  every  99  gallons  of  water  (04  fluid  ounces  to  5  gallons). 

Tar  stock,  for  both  low-strength  and  high-strength  baths,  1  gallon 
added  to  every  300  gallons  of  finished  bath  (2  fluid  ounces,  or  4 
tablespoonfuls,  to  5  gallons).  Mix  the  tar  stock  with  two  or  tlireo 
times  its  volume  of  water  before  adding  to  the  vat.  A  certain  lati- 
tude in  tlie  amount  of  tar  stock  used  is  permissible,  but  it  is  believed 
that  the  above  pro|)ortions  will  be  found  most  satisfactoiy. 

REPLEMISHING   THE  BATH  AND  CORRECTING   ITS   STRENGTH. 

As  dipping  jroes  on,  lh«^  Imth  will  uatunilly  iieetl  replenlBhinjt.  In  addition 
lis  Ktrenntli  will  pmbably  need  correc-tion  from  time  to  time.  'Vtrn  cttuaeg  which 
may  Ic.kI  lu  <lian>,'es  in  llic  .stieiiKtli  of  arwinlcal  batliH,  tonelher  willi  luetliod.s 


>  It  In  VPi-y  llkoly  tlint  till'  l.iin'iui  will  Ihsuo  pin-nilsalon  for  oortnln  proprlrtary  prepii 
rations  to  bo  iihmI  In  oITlrliil  dlppInK'.  Any  such  product  will  bpur  a  statemeiit  ou  tlio 
label  to  till-  i-ITcct  tlint  the  prcliict  Iiiih  l.o.-n  cMiiiiInod  by  tin-  buroiiu  nud  has  bcj-n  por- 
milted  for  use  In  olllclnl  dipping  id:  ii  ^Iven  dilution. 


AKSENICAL   CATTLE   DIPS.  9 

of  chemical  analysis,  have  beeu  elsewhere  discussed  by  the  writer,'  Here  it  is 
sufficient  to  note  that  even  if  all  precautions  are  taken  against  leakage,  either 
in  or  out,  against  evaporation,  and  against  mistakes  In  measurements,  etc., 
still  the  bath  is  likely  to  change  its  strength  owing  to  the  action  of  micro- 
organisms which  grow  therein  in  si:)ite  of  the  presence  of  the  poisonous  arsenic. 
As  already  mentioned,  the  active  ingredient  of  the  bath  is  an  arsenite,  either 
of  sodium  or  i)otassium.  One  species  of  microorganism  is  able»to  take  oxygen 
from  the  air  and  to  combine  it  with  the  arsenite,  thus  forming  an  arsenate,  a 
distinctly  different  compound  of  arsenic,  and  one  which  is  much  les^  poisonous 
to  ticks.  This  species  of  microorganism  appears  to  flourish  in  nearly  all  dip- 
ping baths  under  ordinary  conditions  of  use  and  operates  to  gradually  weaken 
the  bath.  There  is,  however,  another  si^ecies  of  microorganism  which  occa- 
sionally makes  itself  manifest  in  baths  through  which  cattle  are  passed  in  ex- 
ceptionally large  numbers  or  at  frequent  intervals,  and  which  operates  in  pre- 
cisely the  opposite  manner,  namely,  to  reduce  any  arsenate  which  may  be 
present  to  arsenite,  thus  rendering  the  bath  stronger. 

The  chemical  analysis  of  arsenical  baths  with  sufficient  accuracy  for  practi- 
cal purposes  is  not  a  difficult  matter.  It  does,  however,  require  some  chemical 
training  and  equipment  If  State  officials  concerned  with  dipping  can  not 
make  provision  for  the  execution  of  analyses,  it  should  not  be  difficult  to  find 
someone — physician,  veterinarian,  pharmacist,  instructor  in  school  or  college, 
or  even  a  student — who.  for  a  fee.  which  might  be  comparatively  small  if  a 
sufficient  number  of  samples' from  various  sources  could  be  counted  on,  would 
find  it  worth  while  to  undertake  this  work.  It  is  desirable  to  have  the 
"  actual  arsenious  oxid  " — that  is,  the  amount  of  arsenic  existing  as  arsenite — 
determined  at  least  once  a  month,  and  the  "  total  arsenious  oxid " — that  is, 
the  amount  of  arsenic  existing  as  both  arsenite  and  arsenate — determined  at 
least  every  two  months.  To  avoid  danger  of  poisoning  cattle,  it  is  safer  to 
discard  the  bath  entirely  whenever  the  "total  arsenious  oxid"  would  rise 
above  0.25  per  cent  for  the  low-strength  bath  or  above  0.30  per  cent  for  the 
high-strength  bath  after  the  bath  had  been  adjusted  to  contain  the  proper 
amount  of  "  actual  arsenious  oxid." 

In  taking  samples  for  analysis  certain  precautions  are  necessary.  First, 
the  bath  must  be  well  stirred;  next,  the  sample  is  filled  at  the  vat  side  into 
the  bottle  in  which  it  is  to  be  sent  to  the  analyst.  The  bottle  should  hold  not 
less  than  4  fluid  ounces  (one-fourth,  pint)  and  should  be  filled  up  to  the  neck. 
Unless  the  sample  can  be  placed  in  the  hands  of  the  analyst  in  a  very  few 
hours  it  should  be  treated  with  formaldehyde  to  preserve  it  from  the  action  of 
microorganisms  which  may  affect  the  arsenic  and  which  may  work  very  rapidly 
in  the  sample  after  its  removal  from  a  comparatively  cool  location  under- 
ground and  exposure  to  hot  summer  weather.  A  little  concentrated  formalde- 
hyde solution  (37  per  cent)  may  be  cheaply  obtained  from  the  druggist,  to- 
gether with  a  medicine  dropper.  The  formaldehyde  is  to  be  carefully  added 
to  the  sample  with  the  medicine  dropper,  in  the  proportion  of  exactly  .5  drop-s 
to  each  4  ounces  of  sample  (20  drops  to  a  pint).  The  bottle  is  then  to  be 
immediately  corked,  the  cork  and  lip  of  bottle  wiped  dry  and  completely 
covered  with  melted  sealing  wax,  rosin,  or  some  similar  material,  in  order  to 
exclude  air.  A  few  matches  will  furnish  the  heat  necessary  for  melting  the 
sealing  material.  The  analyst  should  be  informed  of  exactly  what  steps  were 
taken  in  preparing  the  samples,  and  the  latter  should  be  shipped  to  him  without 
delay. 

'  1  Department  of  Agriculture  Bulletin  76. 


10  FAKMERS'    BULLETIN    603. 

There  are  two  methods  of  attacking  the  problems  of  rejilenishing 
a  bath  and  of  correcting  its  strength — (1)  method  by  weight  and  (2) 
method  by  volume. 

The  method  hy  weight. — This  method  bases  all  calculations  upon 
the  weight  of  white  arsenic  which  actually  is  in  the  vat  and  the 
weight  which  ought  to  be  in  the  vat.  Table  1  *  gives  the  weight  of 
white  arsenic  which  is  actually  present  in  baths  of  various  volumes 
and  of  varying  percentages  of  arsenious  oxid. 

When  the  quantity  of  bath  in  the  vat  lies  outside  the  range  of  the 
figures  given  in  Table  1  it  will  only  be  necessary  to  multiply  or  to 
divide  by  2.  For  example,  if  the  bath  amounts  to  750  gallons  it  must 
evidently  hold  only  half  as  much  arsenic  as  if  it  amounted  to  1,500 
gallons.  If,  on  the  other  hand,  it  is  desired  to  more  accurately 
employ  figures  which  lie  between  those  given  in  the  table,  either  for 
volume  of  bath  or  for  percentage  or  weight  of  arsenic,  it  is  only 
necessary  mentally  to  split  the  difference  between  the  figures  actually 
given. 

The  manner  in  which  Table  1  is  used  may  be  illustrated  as  follows : 

Suppose  one  needs  to  replenish  and  correct  a  bath  which  is  containetl  in  a 
vat  holding  1,500  gallons  to  the  full  water  line.  He  finds  that  he  has  in  the 
vat  1,050  gallons  of  bath  which  his  analyst  informs  him  contains  0.14  per 
cent  actual  arsenious  oxid.  Looking  up  these  figures  in  the  table,  he  finds 
that  they  indicate  12^  pounds  of  arsenious  oxid  in  the  vat.  What  he  wants  is 
a  vat  filled  with  solution  of  proper  dipping  strength,  we  will  say,  of  the  low- 
strength  formula.  Now,  the  low-.strength  formula  calls  for  0.19  per  cent 
actual  arsenious  oxid,  and,  as  before  stated,  his  vat  holds  1,500  gallons  to  the* 
full  water  line.  Looking  up  these  figures  in  the  table,  he  finds  that  his  vat 
when  filled  with  solution  of  proi^er  strength  must  contain  23|  pounds  of 
arsenious  oxid.  Therefore,  in  filling  his  vat  to  the  full  water  line  he  must 
introduce  23f  less  12i  pounds  of  white  arsenic,  or  11^  i>ounds. 

Having  found  from  Table  1  the  weight  of  white  arsenic  necessary 
to  add  to  the  vat,  subsequent  procedure  depends  upon  the  kind  of 
dip  used.  In  the  case  of  boiled  dip  prepared  on  the  spot,  it  is 
simply  necessary  to  weigh  out  the  proper  amount  of  arsenic  and  to 
boil  it  with  the  corresponding  amount  of  sodium  carbonate,  water, 
etc.  In  case  the  low-strength  boiled  arsenic  stock  is  to  be  employed, 
it  is  necessary  to  remember  that  it  carries  1  pound  of  arsenious 
oxid  in  every  3^  gallons.  Therefore,  multiply  the  number  of  pounds 
of  white  arsenic  needed  by  3^  in  order  to  find  the  number  of  gallons 
of  low-strength  boiled  arsenic  stock  to  be  added.  In  C4ise  of  the 
S-B  ar.senic  stock,  there  is  present  2  pounds  of  arsenious  oxid  in 
every  gallon.  Therefore,  divide  the  number  of  pounds  of  white 
arseni(;  desired  by  2  in  order  to  obtain  the  corresponding  numlM?r  of 
gallons  of  S-B  arsenic  stock. 

The  high-strength  lM)iled  ai^senic  stock,  of  course,  carries  1  ])onnd 
of  white  arsenic  in  each  2 A  gallons. 


1  Credit  for  this  form  of  UI>1o  1b  due  (o  Dr.  G.  A.  Ilandloj',  votorlnnry  Inspector  In  this 
burcuu. 


ABSENIOAL   CATTLE   DIPS. 


11 


Table  1. — Table  for  finding  pounds  of  ivhite  arsenic  in  vat. 


Liquid 
in  vat. 


Per  cent  actual  arsenious  oxid  in  bath. 


Gallons. 
1,000.... 
1,050.... 
1,100„... 
1,150.... 
1,200.... 
1,250.... 
1,300.... 
1,350.... 
1,400.... 
1,450.... 
1,500.... 
1,600.... 
1,700.... 
1,800.... 
1,900.... 
2,000.... 


Lbs. 
10 

m 
11 

Hi 
12 
12i 
13 

m 

14 
Hi 
15 
16 
17 
18 


Lbs. 

Hi 
12 

13 
13J 
14 
Ui 
15 
15i 
16i 
17i 
18i 
191 

21i 


Lbs. 
Hi 

m 

12f 

14 
14i 
15 
15i 
16i 

m 

19f 
21 
22 
231 


Lbs. 
14 
14i 
15i 
16i 
17 

m 
m 

19 
19i 

m 

211 
22i 
24 
25J 
26| 
281 


Lbs. 
20f 
21J 
22f 
24 
25 
26 
27 


1  This  column  may  be  taken  as  representing,  nearly  enough,  correct  weights  of  white  arsenic  for  the  low- 
strength  bath. 
'  This  column  represents  correct  weights  of  white  arsenic  for  the  high-strength  bath. 

The  method  by  volume. — This  method  naturally  applies  only  to 
the  use  of  stock  solutions,  not  to  cases  where  the  desired  amount  of 
white  arsenic  is  to  be  weighed  out  and  dissolved  on  the  spot.  The 
facts  needed  to  start  on  are  exactly  the  same  in  both  methods;  that 
is,  one  must  know  the  capacity  of  the  vat  at  the  full  water  line,  the 
amount  of  bath  actually  in  the  vat,  and  its  strength  expressed  as 
per  cent  of  actual  arsenious  oxid.  The  problem  really  resolves  itself 
into  correcting  the  strength  of  the  bath  already  in  the  vat,  for  when 
this  has  been  done  it  is  simply  necessary  to  fill  up  the  remaining 
space  in  the  vat  with  bath  of  the  regular  strength.  Calculations  are 
simplified  by  the  use  of  Table  2. 
Table  2.— Amount  of  arsenic  stock  necessary  to  correct  each  100  yaUon.s  bath. 


I 


Per  cent  actual 

arsenious  oxid 

m  bath. 

For  low-strength  bath- 

For  high-strength  bath- 

Add  low- 
strength  boiled 
arsenic  stock. 

Add  S-B 
arsenic 
stock. 

Add  high- 
strength  boUed 
arsenic  stock. 

Add  S-B 
arsenic 
stock. 

Per  cent.^ 

Qallons. 

GaJhyns. 

QaUons. 

Gallons. 

0.10 

2.46 

0.38 

G) 

G) 

.11 

2.18 

.34 

(') 

G) 

.12 

1.91 

.29 

2.62 

0.50 

.13 

1.64 

.25 

2.40 

.46 

.14 

1.36 

.21 

2.18 

.42 

.15 

1.09 

.17 

1.96 

.38 

.16 

.82 

.13 

1.74 

.34 

.17 

.55 

.08 

1.53 

.29 

.18 

.27 

.04 

1.31 

.25 

.19 
.20 
.21 

1.09 
.87 
.65 

.21 
.17 
.13 

.22 

.44 

.08 

.23 

.22 

.04 

1 

A  bath  less  than  half  the  desired  strength  should  be  discarded  entirely. 


12  farmers'  bulletin  603. 

To  show  the  manner  uf  usiug  Tiible  ~,  the  same  example  may  be  taken  as 
served  to  illustrate  Table  1,  namely,  a  1,500-gallon  vat  that  contains  1,050 
gallons  of  hath  ;inaly7.iiig  0.14  per  cent  actual  arseuious  oxid.  which  is  to  be 
brought  to  the  full  water  line  with  standard  low-strength  bath.  Supix)se 
that  low-strength  boiled  arsenic  stock  is  to  be  employed.  From  Table  2  it 
will  be  found  that  each  ItJO  gallons  of  0.14  i>er  cent  bath  requires  1.30  gallons 
of  low-strength  boiled  ar.senic  stock  to  bring  it  to  the  right  strength,  so  for 
1,050  gallons  there  is  needed  104X1.36=14.28  gallons  of  stock,  which  would 
bring  the  whole  volume  to  1,050+14=1,064  gallons  of  proper  strength  bath. 
There  is  then  left  1.5<H)— 1,064=436  gallons  of  regular  low-strength  bath, 
which  must  also  be  introduced  to  fill  the  vat,  for  which  there  is,  of  course, 
needed  464-^-20' =23. 2  gallons  of  boiled  arsenic  stock.  Now,  14.28+23.2=37.48, 
or  practically,  S~i  gallons  of  boiled  arsenic  stock  altogether.  Therefore  water 
will  be  run  into  the  vat.  about  6  quarts  of  tar  stock  being  added  during  the 
process  as  called  for  by  the  volume  of  fresh  liquid  iutroduce<l,  finally  leaving 
just  enough  room  below  the  full  water  line  for  37i  gallons  of  low-strength 
boiled  arsenic  stock  which  is  carefully  measured  in. 

It  appears  not  worth  while  to  give  a  table  for  reducing  baths  if 
they  are  found  by  analysis  to  be  too  strong.  This  event  but  seldom 
occurs,  and  if  it  does  the  amount  of  water  to  be  added  may  be  easily 
calculated.  If,  for  example,  a  bath  analyzes  0.25  per  cent  actual 
arsenious  oxid  and  is  to  be  reduced  to  0.19  per  cent,  then  each  100 
gallons  should  be  diluted  to  make  100Xt|=131^  gallons — that  is, 
31^  gallons  of  water  must  be  added  to  each  100  gallons  of  bath  in 
the  vat. 

OBTAINING  THE  CAPACITY  OF  A  VAT. 

To  obtain  the  capacity  of  a  dipping  vat  the  following  measure- 
ments must  be  taken:  (1)  Length  of  the  bottom;  (2)  width  of  the 
bottom  at  its  middle  point;  (3)  length  of  water  line;  (4)  width  of 
water  line  at  its  middle  point;  (5)  vertical  depth  of  dip  at  middle 
of  bottom — that  is,  at  the  same  point  where  measurement  No.  2  was 
taken.  For  future  reference  it  is  Avell  to  mark  this  point  on  the  side 
of  the  vat.  The  measurements  should  be.  carried  to  the  nearest  inch 
for  length,  to  the  nearest  half  inch  for  depth,  and  to  the  nearest 
(|uarter  inch  for  width. 

The  measurements  taken  in  feet  and  inches  are  now  to  be  reduced 
to  feet  and  decimals  of  feet  through  Table  3. 

1  See  page  8. 


ARSENICAL    CATTLE    DIPS. 
Table  3. — Equivalents  of  linear  inches  and  decimals  of  I  foot. 


13 


Linear 

Decimal 

Linear 

Decimal 

Linear 

Decimal 

inches. 

of  1  foot. 

inches. 

of  1  foot. 

inches. 

of  1  foot. 

4 

0.33 

8 

0.67 

i 

0.02 

4i- 

.36 

8} 

.69 

i 

.04 

4i 

.38 

8i 

.71 

a 

.06 

41 

.40 

8i 

.73 

1 

.08 

5 

.42 

9 

.75 

l\ 

.10 

5i 

.44 

9i 

.77 

^ 

.13 

5i 

.46 

9i 

.79 

n 

.15 

5f 

.48 

n 

.81 

2 

.17 

6 

.50 

10 

.83 

2i 

.19 

6i 

.52 

lOi 

.85 

2i 

.21 

6^ 

.54 

lOJ 

.88 

2| 

.23 

61 

.56 

lOJ 

.90 

3 

.25 

7 

.58 

11 

.92 

3i 

.27 

Vi 

.60 

Hi 

.94 

31 

.29 

Vi 

,  .63 

lU 

.96 

3i 

.31 

VJ 

.65 

UJ 

.98 

There  is  an  old,  much-used  rule  for  obtaining  the  capacity  of  a 
dipping  vat  which,  though  somewhat  inaccurate,  possesses  the  marked 
advantages  of  being  easily  grasped  and,  therefore,  of  not  being  liable 
to  error  in  its  application  and  of  being  readily  worked  out  inde- 
pendently if  partially  forgotten.  This  approximate  rule  for  present 
purposes  may  be  stated  as  follows:  Multiply  the  average  length  hy 
the  average  width.,  the  product  hy  the  depth.,  and  this  product  hy  1\.^ 
The  average  length  is  of  course  obtained  by  adding  the  bottom  length 
to  the  water-line  length  and  dividing  the  sum  by  2;  the  average 
width  is  obtained  in  the  same  manner. 

The  rule  may  be  thus  expressed  as  a  formula : 

top  length  +  bottom  length     top  width  +  bottom  width 

-  ^      ~—  X  Q  X  cleptu  X  •Y  — 

approximate  gallons  capacity. 

As  previously  noted,  the  results  given  by  this  rule  or  formula  are 
not  quite  accurate.  In  fact,  it  does  not  account  for  the  upper  corners 
of  the  vat  at  the  exit  incline,  and  so  the  vat  really  holds  somewhat 
more  dip  than  thus  calculated.  The  volume  of  this  additional  por- 
tion of  the  vat  may  be  easily  calculated  after  the  following  correction 
rule :  Multiply  half  the  difference  of  the  lengths  hy  half  the  difference 
of  the  widths,  the  product  hy  the  depth.,  and  this  product  hy  2^.* 

Expressed  as  a  formula  the  correction  becomes : 


X  depth  X  2^^ 


top  length  —  bottom  length     top  width  — bottom  width 

_  .  ^x  2 

additional  gallons  capacity. 

1  The  precise  figure  is  7.48  ;  that  is,  the  number  of  gallons  in  one  cubic  foot. 
=  That  is,  by  one-third  of  7L     Mathematically  the  correct  order  is  to  multiply  by  one- 
third  the  depth,  then  by  7i.     Practically,  of  course,  the  result  is  the  same. 


14 


FABMEBS'   BULLETIN   603. 


This  correction,  added  to  the  approximate  volume  first  found,  gives 
the  true  capacity  of  the  vat  as  nearly  as  it  is  possible  to  calculate  it, 
though  if  the  vat  is  unevenly  constructed,  no  formula  can  be  entirely 
accurate. 

To  illustrate  the  whole  process  of  calculating  the  capacity  of  a  vat,  we  will 
suppose  that  a  vat  has  been  constructed  after  the  plans  and  specifications  of 
the  bureau  elsewhere  given.  The  measurements  as  taken,  and  as  reduced  to 
decimals  through  the  use  of  Table  3,  are  the  following: 


Reduced  to 
decimals. 


Bottom  length . . . 
Bottom  width . . . 
Water-lme  length 
Water-line  width. 
Depth 


12.0 
1.5 

22.8 
2.71 
5.25 


In  reducing  to  decimals,  lengths  need  be  carried  only  to  the  nearest  tenth, 
but  width  and  depth  should  be  carried  out  to  hundredths.  Throughout  subse- 
quent calculations  an  accuracy  greater  than  1  per  cent  is  unnecessary,  hence 
decimal  places  should  be  cut  off  when  multiplying  so  that  each  number  multi- 
plied, unless  a  whole  number,  shall  contain  not  more  than  three  figures. 

Applying  the  approximate  rule: 

(1)  (2)            (3)  (4)  (5) 

22.8  2.71        17.4  36.7  193 

-fl2.0  +1-50  X  2.11  X5. 25  X     7^ 

2)    34.  8  2)    4.  21        36.  714  192.  675  1, 448  gallooB,  approximate  capacity. 


17.4 


2.11 


Applying  the  correction : 

(1) 

22.8 

-12.0 


(2)  (3)  (4)  (5) 

2.71         5.4  3.29  17.3 

L50     X  .61      X5.25       X      2J 


2)     10. 8     2)     1.21 
5.  4  .  61 


294      17.  2725       43.  3  gallons,  correction. 


The  correct  figure  for  the  capacity  of  the  vat  is,  therefore,  1.448+43=1,491 
gallons. 

CONSTRUCTING  A  MEASURING  ROD  FOR  THE  VAT. 

In  replenishing  or  strengthening  dipping  fluids  it  is  frequently 
necessary  to  ascertain  just  how  many  gallons  of  fluid  are  contained 
in  a  partially  filled  vat.  Taking  the  water-line  measurements  and 
then  calculating  tlie  contents  is  inconvenient  and  may  sometimes 
seriously  dehiy  dipping  oi)erations.  Therefore  it  is  desirable  to  con- 
struct a  measuring  rod  Avhich  will  give  directly  the  number  of  gallons 
of  li(iuid  in  tho  vat  at  any  time.    Of  course  such  a  rod  may  bo  grad- 


ABSENICAL   CATTLE   DIPS,  15 

uated  by  measuring  successive  known  volumes  of  water  into  the  vat 
and  marking  on  the  rod  the  depth  of  each  Imown  volume,  but  in  many 
cases  graduation  through  calculation  may  be  more  practicable. 

The  first  step  is  to  calculate  the  water-line  measurements  at  half 
depth  and  then  at  three-quarter  depth.  A  little  consideration  will 
show  that  the  water-line  measurements  at  half  depth  are  exactly 
half-way  between  the  bottom  measurements  and  the  water-line  meas- 
urements of  the  completely  filled  vat;  that  is,  they  are  the  average  of 
these  two  measurements,  obtained  by  adding  them  together  and  divid- 
ing by  two.  In  the  same  way  the  water-line  measurements  at  three- 
quarter  depth  are  the  average  of  the  water-line  measurements  at 
half  depth  and  at  full  depth. 

The  second  step  is  to  calculate  the  capacity  of  the  vat  when  filled 
to  three-quarter  depth.  Then,  having  prepared  a  straight,  smooth 
stick,  7  or  8  feet  long  and  about  1^  inches  square,  lay  off  from  one  end 
(marked  "  bottom  ")  the  feet  depth  at  the  three-quarter  level,  and  mark 
the  point  with  a  pencil  line,  also  adding  the  figure  for  gallons  capac- 
ity at  that  point. 

Third,  subtract  the  capacity  at  three-quarter  depth  from  the  capac- 
ity at  full  depth,  point  back  to  the  left  two  decimal  places  in  the 
remainder,  and  divide  it  into  one- fourth  of  the  actual  full  depth  in 
feet.  The  quotient  is  the  average  number  of  feet  increase  in  depth 
per  100  gallons  liquid  above  the  three-quarter  level. 

Fourth,  subtract  the  actual  capacity  at  the  three-quarter  level 
from  the  next  even  100  gallons  above  that  level  and  set  this  figure 
as  the  numerator  of  a  fraction  of  which  100  is  the  denominator.  By 
this  fraction  multiply  the  figure  for  feet  per  100  gallons,  obtained  in 
the  third  operation.  The  product  is  the  distance  to  be  laid  off  on 
the  rod  above  the  three-quarter  depth  point  to  obtain  the  level  of 
the  next  even  100  gallons  above  that  point.  By  referring  to  Table 
3,  convert  this  distance  to  inches  and  lay  it  off  on  the  rod  with 
proper  notation.  Now,  having  obtained  this  point  for  an  even  100 
gallons,  it  is  only  necessary  to  continue  therefrom,  marking  off  the 
level  of  each  succeeding  100  gallons  by  using  the  figxire  obtained  for 
"  depth  per  100  gallons."  The  same  figure  can  be  used  to  obtain 
capacities  only  a  short  distance  below  the  three-quarter  level  with- 
out serious  error.  But  by  a  similar  series  of  calculations  it  is  pos- 
sible to  obtain  the  capacity  at  half  depth,  then  the  true  average  figure 
for  feet  per  100  gallons  between  half  depth  and  three-quarter  depth, 
and  so  to  graduate  the  rod  between  those  two  levels. 

The  graduations  are  to  be  made  permanent  by  saw  cuts  or  notches, 
50-gallon  marks  being  interpolated  if  desired,  and  the  corresponding 
figures  are  cut  into  the  wood. 


16 


FABMERS'   BULLETIN   603. 


Aa  example  may  make  the  whole  operatiou  clearer.     Taking  the  vat  already, 
used  to  illnsti-iite  the  method  of  obtaining  total  capacity  (p.  14),  we  first  makJ 
the  followiug  table  of  dimensions:                                                                                    1 

Vat. 

At  full 
depth. 

At  hall 
depth. 

At  ihree- 
quarier- 
depth. 

\V  ater-Iine  length 

Feet. 
22.8 
2.71 
12.0 

Feet. 

17.4 
2.11 

12.0 
1.5 
2.63 

Feet. 

Water-line  width 

2.4 
12  0 

Bottom  length 

Bottom  width 

Depth 

5. -25 

3.9 

Second,  we  calculate  the  capacity  at  three-quarter  depth    (3.94  feet)    to 
956  gallojxs.     From  Table  3,  0.94  foot  is  found  to  be  equal  to  lU  inches;  hencej 
at  3  feet  11^  inches  from  the  bottom  end  of  the  rod  is  made  the  mark  for 
capacity  of  956  gallons. 

Third,  knowing  the  full  capacity  to  be  1,491  gallons;  1,491—956=535  gallons! 
or  5.35  hundreds  of  gallons  space  in  the  vat  between  the  three-quarter  and  fullj 
depth  le,v;.o,  which  corresponds  to  5.25-^-4=1.31  feet  difference  in  depth] 
1.31-^5.35=0.245  foot  per  100  gallons. 

Fourth,   1,000—956=44  gallons'.  ^  X0.245=0.108  foot,   corresponding  to 
gallons.     From  Table  3.  0.108  foot=li  inches  (nearly),  so  on  the  rod  li  inchc 
above  the  mark  for  956  gallons  is  made  a  mark  for  1,000  gallons.     Then,  fron| 
the  1,000  gallons  mark  is  measured  off  0.245  foot=3  inches  for  1,100  gallons  J 
2X0.245=0.49  foot=6  inches  for  1,200  gallons,  etc. 

The  graduations  necessarily  depart  a  little,  though  not  much,  frod 
the  true  points  for  levels  between  the  fixed  points  established  by  cal^ 
culation.  One  may,  if  familiar  with  the  process  of  "  plotting,"  laj 
off  these  fixed  points  from  depths  on  one  axis  and  capacities  on  the 
other,  and  so  construct  the  "  curve  "  of  the  capacity  of  the  vat. 

THE  SAFE  DISPOSAL  OF  WASTE  ARSENICAL  BATHS. 

Previous  publications  of  the  department  have  advised  that  whei 
vats  are  emptied  for  cleaning,  the  waste  dip  should  not  be  flowed  ovei 
land  or  vegetation  to  which  domestic  animals  have  access,  or  froi 
whence  it  may  find  its  way  into  water  supplies,  but  should  preferablvl 
be  run  into  a  properly  located  pit  protected  by  a  fence. 

Dalrymple  and  Kerr^  have  proposed  to  add  slaked  lime  and  copj 
peras  to  waste  dip  in  the  vat  in  order  to  throw  down  arsenic  in  ai 
insoluble  form,  thus  allowing  the  overlying  liquid,  after  settling,  tc 
be  disposed  of  as  if  arsenic  free.  The  method  retiuires  very  thor-j 
ough  stirring  in  order  that  the  difficultly  soluble  lime  may  produce 
the  desired  effect.  Wliether  the  necessary  stirring  can  be  accom^ 
plished  in  large  vats  with  sufficient  thoroughness  to  render  tht 
method  reliable  under  practical  conditions  on  a  large  scale  may  be 
(luestionable. 


'Bulletin  132,  Louisiana  .\KrlculturaI  Experiment  Station,  1911 
discrlptlon  of  the  nii'tliod  is  ii\vcn  in  Fnrnifrs"  Bulletin  408  and  li 
Industry  Circular  207  of  the  T'.  S.  Department  of  .VKrUullurc 


A    brief    detnlle<3 
Rureau  of  .\Qimal 


o 


W  A. S II  INC  TON  :  GOVEH.SMK.VT  TKINTING  OmCB  :  1014 


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